Constructed wetland technology as an innovative water treatment method

Abstract Introduction: the innovative technology of constructed wetlands (CW) allows removing a wide range of pollutants from the waste water, while minimizing the use of mechanical equipment and chemical reagents as well as systems of process monitoring. As a result, it permits to save the energy and human resources without declining the efficiency of the process. The purpose of the study is to analyse and evaluate the functionality of existing CW technologies and determine the conditions of their application. Materials and methods: in the case study, the data obtained by Ambiente Italia and the results of existing studies on the efficiency of the various CW technology types are presented according to the following indicators of water treatment: BOD5, COD, total nitrogen and total phosphorus, ammonium nitrogen, suspended solids, pathogens. The relationship of these indicators with the physics of the process occurring in the CW basin was analysed. Results: five main CW technology types and expediency of their application depending on various factors are described. Practical recommendations are given on the choice of structural solutions and materials as well as on the calculation procedure of each specific type of CW technology. Conclusions: for every specific case it must be made a reasonable choice of CW type. For tertiary treatment of small wastewater flows as well as the choice in favour of the simplest solution, FWS technology is well-proven, while for high water flowrates and high levels of organic loads, the HF technology is suitable. At the same time, HF has inferior efficiency with respect to the VF technology in terms of total and ammonium nitrogen removal. However, VF is limited by the condition of variable operation (with pauses), whereas HF operates at constant flow rates. At the same time, VF guarantees better inhibition of pathogens and influent filtration.